Hai-Yan Tao

Catalytic asymmetric 1,3-dipolar cycloaddition of N-unprotected 2-oxoindolin-3-ylidene derivatives and azomethine ylides for the construction of spirooxindole-pyrrolidines

Asymmetric 1,3-dipolar cycloaddition of N-unprotected 2-oxoindolin-3-ylidene with azomethine ylides for the construction of spirooxindole-pyrrolidines bearing four contiguous stereogenic centers has been achieved with AgOAc/TF-BiphamPhos complexes for the first time. This catalytic system performance well over a broad scope of substrates, providing the synthetically useful adducts in high yields and excellent diastereoselectivities and moderate enantioselectivities.

Catalytic Asymmetric Synthesis of [2,3]‐Fused Indoline Heterocycles through Inverse‐Electron‐Demand Aza‐Diels–Alder Reaction of Indoles with Azoalkenes

An unprecedented catalytic asymmetric inverse-electron-demand aza-Diels-Alder reaction of indoles with in situ formed azoalkenes is reported. A diverse set of [2,3]-fused indoline heterocycles were achieved in generally good yields (up to 97 %) with high regioselectivity and diastereoselectivity (>20:1 d.r.), and with excellent enantioselectivity (up to 99 % ee).

Catalytic Asymmetric 1,3‐Dipolar Cycloaddition of Two Different Ylides: Facile Access to Chiral 1,2,4‐Triazinane Frameworks

Ylides at a crossing: An unprecedented 1,3-dipolar cycloaddition (cross-cycloaddition) between two different ylides was realized by using the chiral Cu(I) /tBu-Phosferrox complex as the catalyst under mild reaction conditions. This catalytic system provides an expeditious approach to the construction of highly functionalized 1,2,4-triazinane derivatives in good yields with excellent diastereoselectivities and enantioselectivities.

Stereoselective construction of a 5-aza-spiro[2,4]heptane motif via catalytic asymmetric 1,3-dipolar cycloaddition of azomethine ylides and ethyl cyclopropylidene acetate.

A direct and facile synthesis of highly functional 5-aza-spiro[2,4]heptanes, a valuable structural motif for drug discovery, is developed via catalytic asymmetric 1,3-dipolar cycloaddition of cyclopropylidene acetate and azomethine ylides for the first time.

A facile Cu(I)/TF-BiphamPhos-catalyzed asymmetric approach to unnatural α-amino acid derivatives containing gem-bisphosphonates.

A novel catalytic asymmetric Michael addition of azomethine ylide with β-substituted alkylidene bisphosphates was realized in the presence of a chiral copper(I)/TF-BiphamPhos complex. The present system provides a unique and facile access to enantioenriched unnatural α-amino acid derivatives containing gem-bisphosphonates (gem-BPs) in high yields with excellent diastereoselectivities and enantioselectivities. Subsequent transformations lead to the expedient preparation of biologically active unnatural α-amino acid derivatives containing BPs and bisphosphonic acids without loss of diastereo- and enantiomeric excess.

Silver-catalyzed enantioselective desymmetrization: facile access to spirolactone-pyrrolidines containing a spiro quaternary stereogenic center.

An unprecedented Ag(I)-catalyzed asymmetric desymmetrization of spiro cyclohexadienone lactones has been developed successfully, which performs well over a broad scope of substrates and provides a facile access to optically active spirolactone-pyrrolidines in high yields with excellent levels of diastereo-/enantioselectivities.

Organocatalytic asymmetric domino sulfa-Michael–aldol reactions of 2-mercaptobenzaldehyde with α,β-unsaturated N-acylpyrazoles for the construction of thiochromane

An efficient protocol for the direct construction of bioactive thiochromanes was developed via a catalytic asymmetric cascade sulfa-Michael-aldol reaction of 2-mercaptobenzaldehyde with α,β-unsaturated N-acyl imides. The key to the present methodology is introducing a pyrazole moiety as H-bond acceptor, which allowed for better organization and activation and hence higher enantioselectivity.

Catalytic Asymmetric Cascade Vinylogous Mukaiyama 1,6-Michael/Michael Addition of 2-Silyloxyfurans with Azoalkenes: Direct Approach to Fused Butyrolactones

An unprecedented cascade vinylogous Mukaiyama 1,6-MA/MA of 2-silyloxyfurans and azoalkenes was realized with a Cu(II)/(t)Bu-Box complex. An array of fused butyrolactones containing multiple stereocenters was generally obtained in good yield (up to 90% yield) with exclusive diastereoselectivity (>20:1 dr) and excellent enantioselectivity (up to 99% ee). Carbon isotope effects measured by (13)C NMR revealed a stepwise mechanism for this annulation process.

Highly diastereoselective DABCO-catalyzed [3 + 3]-cycloaddition of 1,4-dithiane-2,5-diol with azomethine imines.

An effective diastereoselective [3 + 3] cycloaddition of 1,4-dithiane-2,5-diol with azomethine imines catalyzed by DABCO is described. A variety of highly functionalized six-membered dinitrogen-fused heterocycles can be obtained in good yield with excellent diastereoselectivity, which was controlled by anomeric effect.

A Facile Access to Enantioenriched Isoindolines via One-Pot Sequential Cu(I)-Catalyzed Asymmetric 1,3-Dipolar Cycloaddition/Aromatization

Facile access to enantioenriched isoindolines bearing a quaternary stereogenic center and a tertiary stereogenic center was successfully developed via highly efficient Cu(I)/(S,Rp)-PPFOMe-catalyzed asymmetric 1,3-dipolar cycloaddition of azomethine ylide with quinone derivatives followed by silica-gel-promoted oxidation [corrected] in a one-pot reaction protocol. The present catalytic system exhibited high diastereoselectivity, excellent enantioselectivity, and a broad substrate scope under mild conditions.